The second feature to be written and directed by the British filmmaker Amma Asante, "Belle" will tell the story of a mixed-race woman raised as an aristocrat in 18^th-century England. Dido Elizabeth Belle (1761-1804) was the illegitimate daughter of Admiral Sir John Lindsay of the British navy and an enslaved woman, herself known as Belle.

The movie is partially inspired by the above painting (artist unknown), in which Dido, wearing a turban, stands to the right of her orphaned cousin, Lady Elizabeth Murray. Both girls were raised by Lindsay’s cousin William Murray, the Earl of Mansfield, and his wife Elizabeth at Kenwood House in Hampstead, near London. It is likely that Dido was adopted as a companion for Elizabeth. She lived at Kenwood for about 30 years.

Asante has cast Gugu Mbatha Raw as Dido in “Belle,” which starts shooting at Pinewood Studios on September 24. The impressive cast also includes Sam Reid, “Harry Potter” alum Tom Felton, Sam Reid, Tom Wilkinson, Miranda Richardson, Matthew Goode, Emily Watson, Penelope Wilton, Sarah Gadon, and James Norton.

Reid will play Dido’s lover, John Davinier, whom she married in 1793. They had three sons and belonged to the parish of St. George’s Church, Hanover Square, near present-day Oxford Circus.

Like Andrea Arnold’s upcoming “Wuthering Heights,” in which black actors play the young and grownup Heathcliffe, “Belle” will bring some urgent racial consciousness to the WASPy world of the British heritage drama.

According to the entry on Dido in Wikipedia, “her position was unusual because she was formally the daughter of a slave, and as such would have been considered a slave outside of Britain. But she was to some extent treated as a member of the family. Lord Mansfield himself resolved this paradox in his capacity as Lord Chief Justice.”

Judging the case of an escaped American slave, James Somersett, in 1772, the dynamic Mansfield decreed that “The state of slavery is of such a nature, that it is incapable of being introduced on any reasons, moral or political....Whatever inconveniences, therefore, may follow from the decision, I cannot say this case is allowed or approved by the law of England; and therefore the black must be discharged.’” Abolitionists received Mansfield’s decision as a sanctioning of abolition in England, although he later said it was only to apply to Somersett.

Dido’s illegitimacy and her race would have been frowned upon by members of the Mansfield’s social circle. She was to some extent discriminated in Mansfield’s household, being barred from dining with the family though allowed to join the ladies for coffee. As a young woman, she took care of the dairy and poultry yards at Kenwood and helped Mansfield with his correspondence, being paid much more for her work than a domestic.

There has previously been a short film, “Dido Belle” (2006), about the only known non-white British heiress of the 18^th century. She has also been central to two plays about the Somerset ruling.